Use 'COLLATE "C"' to force locale-independent sorting of the iexit
view results in select_views.sql. We aren't particularly interested
in the exact sorting behavior here, and this doesn't change the shape
of the generated plan, so it seems like a wash as far as the goals
of this test go.
This is in response to bug #14637 from Tomasz Kontusz. It doesn't
fully resolve his problem, because he also saw some diffs in the
create_index test. But other people have had issues with select_views
too, and this fix lets us drop the select_views_1.out variant expected
file altogether, which is a nice win from a maintenance standpoint.
Emre Hasegeli
Discussion: https://postgr.es/m/20170501000609.24360.24248@wrigleys.postgresql.org
The original security barrier view implementation, on which RLS is
built, prevented all non-leakproof functions from being pushed down to
below the view, even when the function was not receiving any data from
the view. This optimization improves on that situation by, instead of
checking strictly for non-leakproof functions, it checks for Vars being
passed to non-leakproof functions and allows functions which do not
accept arguments or whose arguments are not from the current query level
(eg: constants can be particularly useful) to be pushed down.
As discussed, this does mean that a function which is pushed down might
gain some idea that there are rows meeting a certain criteria based on
the number of times the function is called, but this isn't a
particularly new issue and the documentation in rules.sgml already
addressed similar covert-channel risks. That documentation is updated
to reflect that non-leakproof functions may be pushed down now, if
they meet the above-described criteria.
Author: Dean Rasheed, with a bit of rework to make things clearer,
along with comment and documentation updates from me.
We don't normally allow quals to be pushed down into a view created
with the security_barrier option, but functions without side effects
are an exception: they're OK. This allows much better performance in
common cases, such as when using an equality operator (that might
even be indexable).
There is an outstanding issue here with the CREATE FUNCTION / ALTER
FUNCTION syntax: there's no way to use ALTER FUNCTION to unset the
leakproof flag. But I'm committing this as-is so that it doesn't
have to be rebased again; we can fix up the grammar in a future
commit.
KaiGai Kohei, with some wordsmithing by me.
Drop the role we create, so regression tests pass even when run more
than once against the same cluster, a problem noted by Tom Lane and
Jeff Janes. Also, rename the temporary role so that it starts with
"regress_", to make it unlikely that we'll collide with an existing
role name while running "make installcheck", per further gripe from
Tom Lane.
Tom Lane
Stephen Frost
Peter Eisentraut
Robert Haas
Thomas G. Lockhart
Vadim B. Mikheev
Marc G. Fournier